U.S. patent number 8,228,668 [Application Number 11/828,866] was granted by the patent office on 2012-07-24 for balanced moment lift system and method.
This patent grant is currently assigned to Ergotron, Inc.. Invention is credited to Saeb Asamarai, Robert W. Fluhrer.
United States Patent |
8,228,668 |
Asamarai , et al. |
July 24, 2012 |
Balanced moment lift system and method
Abstract
A lift system having a first pulley and a biasing member having
a first portion operatively coupled to the first pulley. A first
tension member can be operatively coupled to the first pulley. The
lift system may be configured to provide a constant force to the
first tension member during a defined angle of rotation of the
first pulley. Such a constant force can be used to counterbalance
the weight of a display supported by a stand.
Inventors: |
Asamarai; Saeb (Columbia
Heights, MN), Fluhrer; Robert W. (Prior Lake, MN) |
Assignee: |
Ergotron, Inc. (St. Paul,
MN)
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Family
ID: |
38987021 |
Appl.
No.: |
11/828,866 |
Filed: |
July 26, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080026892 A1 |
Jan 31, 2008 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60833503 |
Jul 26, 2006 |
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Current U.S.
Class: |
361/679.05;
248/125.2; 361/679.21; 348/836 |
Current CPC
Class: |
F16M
11/046 (20130101); F16M 2200/041 (20130101) |
Current International
Class: |
G06F
1/16 (20060101); H05K 7/00 (20060101); H04N
5/64 (20060101); F16M 11/00 (20060101) |
Field of
Search: |
;348/836-843
;361/679.05,679.21 ;312/312 ;248/125.2,125.8,157,132 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1091279 |
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1171222 |
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1611809 |
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DE |
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3406669 |
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DE |
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3610612 |
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DE |
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19635236 |
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29908098 |
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DE |
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0183938 |
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EP |
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0202533 |
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1052472 |
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EP |
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0831809 |
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FR |
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2037056 |
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0785363 |
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GB |
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2154442 |
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2338894 |
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JP |
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88200746 |
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Nov 1999 |
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TW |
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0244609 |
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Jun 2002 |
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WO |
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Other References
English-language abstract for DE3406669 (Heckmann). cited by other
.
English-language abstract for DE36106129 (Hados Moebelfabrik).
cited by other .
English-language abstract for DE19635236 (Siemens AG). cited by
other .
English-language abstract for FR2037056 (Westinghouse Electric).
cited by other .
English-language abstract for TW88200746 (Lin). cited by other
.
English-language abstract for JP2003295161 (Kato Electric &
Machinery). cited by other.
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Primary Examiner: Michener; Joshua J
Assistant Examiner: Kwiecinski; Ryan
Attorney, Agent or Firm: Fredrikson & Byron, P.A.
Parent Case Text
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
Ser. No. 60/833,503, filed Jul. 26, 2006, titled Balanced Moment
Lift System and Method, the contents of which are hereby
incorporated by reference.
Claims
What is claimed is:
1. A method of changing a position of a display, comprising
engaging a display and applying a force to the display, the display
being operatively coupled to a lift system comprising a first
pulley having an axis of rotation, a biasing member having a
biasing member force dependent upon its length, a centerline, and a
first portion operatively coupled to the first pulley, a first
radius extending between the centerline of the biasing member and
the axis of rotation, the first radius continuously changing when
the first pulley rotates and the first radius having a value of
zero when the biasing member force is at a maximum to create a
constant moment output, and a first tension member having a first
portion operatively coupled to the first pulley, the constant
moment output providing a constant force to the first tension
member during a defined angle of rotation of the first pulley.
2. A stand and display in combination, comprising: a display; a
stand supporting the display, the stand having a base and a
vertical member coupled to the base, the vertical member having an
inner member and an outer member in sliding or rolling engagement,
one of the inner and outer members functionally coupled to the base
and the other of the inner or outer members functionally coupled to
the display; a lift system disposed within the stand, the lift
system comprising a first pulley having an axis of rotation, a
biasing member having a biasing member force dependent upon its
length, a centerline, and a first portion operatively coupled to
the first pulley, a first radius extending between the centerline
of the biasing member and the axis of rotation, the first radius
continuously changing when the first pulley rotates and the first
radius having a value of zero when the biasing member force is at a
maximum to create a constant moment output, and a first tension
member having a first portion operatively coupled to the first
pulley, the constant moment output providing a constant force to
the first tension member during a defined angle of rotation of the
first pulley to counterbalance the display.
3. The lift system of claim 2, wherein a second portion of the
first tension member is functionally coupled to the display.
4. The lift system of claim 2, further including a second pulley
having a second pulley radius operatively coupled to the first
pulley via a second portion of the first tension member, the second
pulley being operatively coupled to a third pulley having a third
pulley radius, the third pulley radius being larger than the second
pulley radius, the third pulley having a second tension member with
a first portion operatively coupled thereto, the lift system being
configured to magnify the range of motion of a second portion of
the second tension member as the first pulley moves through the
defined angle.
5. The lift system of claim 4, wherein the second pulley and third
pulley have coaxial axes of rotation.
6. The lift system of claim 4, wherein the third pulley radius is
at least twice the length of the second pulley radius.
7. The lift system of claim 4, wherein the second portion of the
second tension member is operatively coupled to the display.
8. The lift system of claim 7, wherein the display is a flat panel
display.
9. The lift system of claim 2, further including a contact member
having a contact surface connected to the first pulley and an
engagement member useful for engaging the contact surface.
10. The lift system of claim 9, wherein the contact surface
includes a generally helical groove in the contact member and the
engagement member includes a rigid protrusion that rides within the
groove.
11. The lift system of claim 9, wherein the contact member includes
a camming member having a camming surface and the engagement member
is useful for engaging the camming surface.
12. The lift system of claim 2, wherein the defined angle is less
than 180 degrees.
13. The lift system of claim 2, wherein the defined angle is less
than 90 degrees.
14. The lift system of claim 2, wherein the defined angle is less
than 30 degrees.
15. The lift system of claim 2, wherein the biasing member includes
a spring.
16. The lift system of claim 15, wherein the spring includes an
extension spring.
17. The combination of claim 2, wherein the base defines a cavity
to house the biasing member and first pulley.
18. The lift system of claim 2, wherein the first portion of the
first tension member is directly connected to the first pulley.
Description
FIELD OF THE INVENTION
The invention relates to balanced moment lift mechanisms useful for
supporting displays.
SUMMARY OF THE INVENTION
In some embodiments, the invention includes a lift system having a
first pulley having an axis of rotation and a biasing member having
a centerline and a first portion operatively coupled to the first
pulley. When the first pulley moves the biasing member will
deflect, thereby changing its length. A distance between the axis
of rotation of the first pulley and the longitudinal centerline of
the biasing member will also change. Accordingly, a constant moment
output can be created through a defined angle of rotation of the
first pulley. A first tension member, such as a cable, can be
operatively coupled to the first pulley. In such embodiments, the
lift system is configured to provide a constant force to the first
tension member during a defined angle of rotation of the first
pulley. Such a constant force is useful, for example, for providing
a counterbalancing force to a display. Embodiments of the invention
also include using such a lift system and a stand with such a lift
system in combination with a display.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a front perspective view of a display and stand in
accordance with an embodiment of the invention.
FIG. 2 shows a top plan view of a lift system in a first position
in accordance with an embodiment of the invention.
FIG. 3 shows the lift system of FIG. 2 in a second position in
accordance with an embodiment of the invention.
FIG. 4 shows a top plan view of a lift system in accordance with an
embodiment of the invention.
FIG. 5 shows the lift system of FIG. 4 in a second position in
accordance with an embodiment of the invention.
FIG. 6 shows a front perspective view of a display and stand with a
lift system in accordance with an embodiment of the invention.
FIG. 7 shows a rear perspective view of a display and stand with a
lift system in accordance with another embodiment of the
invention.
DETAILED DESCRIPTION
The following detailed description should be read with reference to
the drawings, in which like elements in different drawings are
numbered identically. The drawings, which are not necessarily to
scale, depict selected embodiments and are not intended to limit
the scope of the invention. Examples of constructions, materials,
dimensions, and manufacturing processes are provided for selected
elements. All other elements employ that which is known to those of
skill in the field of the invention. Those skilled in the art will
recognize that many of the examples provided have suitable
alternatives that can be utilized.
The following disclosure discusses lift system systems and methods
useful for lifting an object, such as a flat panel display of the
type commonly used as television sets and computer screens. Various
embodiments of the lift systems discussed herein have several
advantages. For example, these lift systems are settable versus
adjustable. This refers to the property of the system that allows
it to position an object at any suitable location with one hand
rather than set into a predefined position using two hands. Second,
these systems are easily maneuverable. For example, lift systems in
accordance with embodiments of the invention are moveable using
less than a predefined percentage of the object weight. For
example, in some embodiments, the lift system and object can be
maneuvered using a force equal to 10% or less of the weight of the
object itself. Third, lift systems in accordance with embodiments
of the invention are infinitely adjustable along the range of
travel rather than locked into position at a series of predefined
points. All of these properties are provided in a lift system that
is low cost to produce and highly reliable.
As shown in FIG. 1, some embodiments of the invention include a
stand 2 having a base 4 and a vertical member 6. As shown, one or
more displays 8 (e.g., flat panel displays, such as liquid crystal
displays (LCDs) or plasma displays) may be coupled the stand 2. It
should be noted that, although only one display is shown in FIG. 1,
multiple displays (e.g., two or more) can be supported by stand 2.
As described further herein, the stand 2 may house a lift system to
provide for the display 8 to be set at any point along a range of
travel relative to the base in an easily maneuverable manner. For
example, the lift system may be housed in a cavity defined by the
base 4 of the stand 2.
In some embodiments, such as the embodiment shown in FIGS. 2 and 3,
the lift system 10 includes a first pulley 20 having an axis of
rotation A and a biasing member 30 (e.g., a spring, such as an
extension spring) with a first portion 40 (e.g., a first end)
operatively coupled to the first pulley 20. "Operatively coupled,"
as used herein, can include, for example, clamps, screws, adhesives
and/or integral formation for a direct type coupling, or the use of
various spacers, trucks and/or brackets for a more indirect type
coupling. In some embodiments, the biasing member is coupled
proximate an outer circumference of the pulley. The biasing member
30 may have a second portion 50 operatively coupled to a support 60
(e.g., a fixed member coupled to the stand, a housing fixed member,
or wall). In some embodiments, the biasing member is free to pivot
about its connection to the pulley and the support. Also shown in
the embodiment of FIGS. 2 and 3, the lift system 10 includes a
first tension member 70 (e.g., a cable or rope) having a first
portion 80 operatively coupled to the first pulley 20. Such a lift
system 10 is useful for providing a constant force to the first
tension member 70 during a defined angle DA rotation of the first
pulley 20. As will be understood by those skilled in the art,
"constant force" or "generally constant force" means an effectively
constant force, such as plus or minus 10% or less (e.g., 5% or
less) of a purely constant force output.
As shown in FIGS. 2 and 3, when the first pulley 20 moves counter
clockwise the biasing member 30 will deflect, thereby changing its
length L and creating a moment equal to Fs*D1, where Fs is the
biasing member force and D1 is the distance between the axis of
rotation of the first pulley 20 and the longitudinal centerline CL
of the biasing member 30. As the first pulley 20 rotates D1 will
decrease until it becomes zero, as shown in FIG. 3. During this
rotation, the biasing member force will increase until it reaches
its maximum when D1 is zero. Accordingly, a constant moment output
can be created through a defined angle DA of rotation of the first
pulley 20 to provide a constant force F1 experienced by the first
tension member. In some embodiments, such a constant moment output
can be achieved until about 10 degrees to about 20 degrees before
D1 becomes zero. Further, the first tension member 70 can be used
to apply a rotating force to the first pulley. In such embodiments,
the force F1 experienced by the first tension member will be
generally constant throughout the first pulley movement through the
defined angle. In some embodiments, the first radius will have a
maximum when the biasing member has a first length and a minimum
when the biasing member has a second length, the second length
being the maximum biasing member length. Further, in certain
embodiments, the biasing member will have a length, and the length
of the biasing member continuously increases as the first radius
continuously decreases during the defined angle of rotation of the
first pulley.
The magnitude of the defined angle, and where it starts and ends,
will depend on the size of the first pulley, the length of the
biasing member at rest, and the distance from where the biasing
member is attached to the support to the first pulley. In some
embodiments, the defined angle is less than about 180 degrees. In
other embodiments, the defined angle is less than about 135
degrees. In yet other embodiments, the defined angle is less than
about 90 degrees. In some embodiments, the defined angle is less
than 45 degrees. In yet other embodiments, the defined angle is
less than about 30 degrees. In some embodiments, the defined angle
is about 15 degrees.
In some embodiments, as shown in FIGS. 4 and 5, the lift system 10
in configured to increase the range of travel of a lifted object,
such as a display, compared to what is provided by the defined
angle DA. For example, the lift system 10 can include a second
pulley 90 with a radius r2 operatively coupled to the first pulley
20 via a second portion 100 of the first tension member 70. In some
embodiments, as shown in FIGS. 4 and 5, the second pulley 90 is
operatively coupled to a third pulley 110 having a radius r3. In
certain embodiments, the second pulley and third pulley are
integrally formed with one another. Further, the second pulley and
third pulley can have coaxial axes of rotation. In some embodiments
the second pulley and third pulley are vertically offset from one
another about a common axis of rotation.
As shown in FIGS. 4 and 5, the radius r2 of the second pulley 90
can be less than the radius r3 of the third pulley 110. In some
embodiments, the third pulley radius is at least about twice the
length of the second pulley radius. In certain embodiments, the
third pulley radius divided by the second pulley radius defines a
ratio, the ratio being greater than about two (e.g., greater than
about 3).
In some embodiments, the third pulley 110 has a second tension
member 120 with a first portion 130 operatively coupled thereto.
The force F1 described above may be transferred to the second
pulley 90 via first tension member 70. When the second pulley 90
turns a full turn, the third pulley 110 will rotate a full turn
too, thereby magnifying the range of motion of a second portion 132
(and any object associated therewith) of the second tension member
120 as the first pulley 20 moves through the defined angle. Since
force F1 is a generally constant force through the defined angle,
force F2 will also be generally constant through this angle.
Accordingly, an object, such as a display, associated with the
second portion of the second tension member can provide a balancing
force generally equal to F1. Such a display will be settable,
easily maneuverable, and infinitely adjustable along the range of
travel.
Although FIGS. 2-5 are referred to as a "top plan" views, it should
be noted that designation is only for purposes of discussion, and
that embodiments of the lift system may be orientated in any
suitable fashion, including vertical and horizontal. Further,
embodiments of the lift system may also be configured to lift an
object in any direction, including vertical and horizontal.
FIG. 6 shows an embodiment of a lift system 10 in a stand 2
supporting a display 8. As shown, in this embodiment the lift
system 10 is housed in a cavity in the base 4 of the stand 2. The
vertical portion 6 of the stand 2 includes an outer member 140
fixed to the base and an inner member 150 fixed to the display 8.
In other embodiments, the outer member will be fixed to the display
and the inner member will be fixed to the base. The inner and outer
members are in sliding or rolling engagement with each other to
allow the display 8 to be set at any height relative to the base
within a defined range of travel. As shown, one or more pulleys 160
may be provided to route the second tension member 120 from the
third pulley 110 to the vertical member 6. As the display 8 is
lowered relative to the base it allows the third pulley 110 to
rotate, in this example, in a clockwise direction. The second
pulley 90 will also rotate in a clockwise direction. The first
pulley 20 will rotate in a clockwise direction and the biasing
member length L will decrease (thereby changing the biasing member
force) while D1 increases to provide a continuously
counterbalancing force to the display as it is moved downward
through its range of motion and to provide the proper
counterbalancing force to hold the display at its new position.
Raising the display causes the first, second, and third pulleys to
rotate in a counterclockwise direction and the biasing member
length L to expand and D1 to decrease to provide a continuously
counterbalancing force to the display as it is moved upward through
its range of motion and in its new desired position.
Another embodiment of the invention is shown in FIG. 7. In the
embodiment shown, first pulley 20 and biasing member 30 are housed
in the base 4 of the stand 2. The biasing member length L (and
associated biasing member force) and D1 cooperatively change
together as the display is moved through its range of motion as
discussed above. In the embodiment of FIG. 7, a contact member 170
(e.g., cam member) having a contact surface 180 (e.g. camming
surface) is connected to the first pulley 20. In some embodiments,
the contact member has a longitudinal axis that coincides with the
axis of rotation of the first pulley. As shown, an engagement
member 190 (e.g., cam engagement member) useful for engaging the
contact surface can be coupled with the display. In some
embodiments, the contact surface takes the form of a helical
groove. In other embodiments, the contact surface takes the form of
a generally serpentine groove in the contact member to provide a
camming surface. Such embodiments are useful for more closely
approximating a pure constant force output. In certain embodiments,
the engagement member includes a rigid protrusion that rides within
the groove. In the embodiment shown, as the display is moved
downwardly relative to the base the engagement member rides within
the groove and interacts with the contact surface. The interaction
causes the contact member and the first pulley to move in a
counterclockwise direction. As the first pulley rotates the biasing
member length L will increase while D1 decreases to provide a
continuously counterbalancing force to the display and it is moved
downward through its range of motion and to provide the proper
counterbalancing force to hold the display at its new position.
Raising the display causes the cam member to rotate in a clockwise
direction and the biasing member length L to decrease and D1 to
increase to provide a continuously counterbalancing force to the
display as it is moved upward through its range of motion and in
its new desired position.
Embodiments of the invention also include methods of making and
using the various embodiments of lift systems described above. For
example, in use, a lift system as described above can be provided.
When a user desires to change the position of the display, such as
by raising it, the user can manually engage the display and apply a
force in the vertical direction. In some embodiments, such a
movement will cause the third pulley 110 to rotate. The second
pulley 90 attached to the first tension member 70 will rotate in
the same direction. In other embodiments, rotation of a contact
member will cause the first pulley to rotate. The first tension
member 70 will cause the first pulley 20 to rotate through its
defined angle, causing an extension of the biasing member. Because
the moment Fs*D1 is constant as the first pulley 20 moves through
its defined angle as described above, the resistance force
experienced by the user during the repositioning is relatively
constant. In addition, because the force is counterbalanced, the
user will be able to reposition the display using a force equal to
a fraction of the weight of the display.
Numerous characteristics and advantages of the invention covered by
this document have been set forth in the foregoing description. It
will be understood, however, that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size and ordering of steps
without exceeding the scope of the invention.
* * * * *